1. Field of the Invention
This invention relates to a solid bowl or drum helical conveyor centrifuge having a rotating drum, which includes a centrifuge space with a screw that can rotate and having an inlet tube for supplying a material for centrifugation into the centrifuge space.
2. Description of Prior Art
To ensure pressure-tight and airtight operation of a solid drum helical conveyor centrifuge, it is known that the entire drum (i.e., the entire rotating area of the drum) can be surrounded with a housing that is sealed with respect to the environment.
Within this housing, it is possible to maintain the boundary conditions of the process to be carried out and to move the mass flows under the desired pressure conditions.
The friction occurring in particular between the gas molecules and the drum surface, especially at high rotational speeds and/or large diameters of the drum, requires considerable driving power and increases the power consumption by the centrifuge in a manner that is a disadvantage. Another problem is that this energy causes heating of the gas and the rotating part. The wall friction increases in proportion to the increase in pressure and thus there is also an increase in required driving power.
This will now be explained in greater detail on the basis of an example.
If the pressure in a conventional commercial solid bowl helical conveyor centrifuge is increased from 0 bar to 5 bar, for example, it is quite possible for the frictional energy to be increased by a factor of approximately 5 (e.g., from 10 kW to 50 kW or from 100 kW to 500 kW, depending on the diameter and/or the type of machine).